“The opposition leader Kem Sokha has now been jailed for nearly a year on preposterous treason charges, because he had the audacity to lead an opposition party in Cambodia,” Brad Adams, Asia director of Human Rights Watch, said in a statement last month.

“Governments concerned about the end of democratic rule in Cambodia should demand the immediate release of Kem Sokha and all other political prisoners.”

Kem Sokha’s Cambodia’s National Rescue Party (CNRP) was dissolved in November and all of its 118 senior members were barred from politics for five years in a government crackdown on critics.

Long-standing Hun Sen oversaw the shuttering of independent media organisations, the imprisonment of prominent activists and critics, and the complete removal of any credible opposition in the months leading up to July’s general election.

The crackdown ensured victory for his Cambodia People’s Party (CPP) who secured all 125 parliamentary seats.

Following the election, Hun Sen requested royal pardons for 14 government critics who were freed last month. Hopes that Kem Sokha’s release may follow were dashed, however, after he was denied bail for a second time in late August.

Among the health problems exacerbated by his detention are high blood pressure, severe pain in his shoulder, and diabetes. His lawyers reported that he now has difficulty standing up for long periods.

Criticism of Hun Sen’s human rights record has been mounting in recent years. Under increased pressure from western governments to improve the situation, the former Khmer Rouge general has turned his sights to China, receiving huge financial backing from Beijing. Observers believe it may be this support that enabled him to carry out the political crackdown and carry out an election that was described as “flawed” and the “death of democracy.”